1. Field of the Invention
This invention relates to an access device for inline installation to drain lines and other fluid transfer conduits and, more particularly, to an inline access device that allows for cleaning and removing clogs in air conditioning and refrigeration condensate drain lines and other fluid transfer lines, and wherein the access device is equipped with an internal overflow safety switch.
2. Discussion of the Related Art
In various systems and equipment, there is a need to transfer and/or drain liquid from the equipment to a separate location. For example, in air conditioning and refrigeration systems, condensation naturally occurs as warm, humid air passes over the exterior of the evaporator coil in the HVACR unit. Typically, the condensation drips from the evaporator coil into a condensate collection pan positioned below the evaporator coil. From the collection pan, the liquid condensate is directed through a drain line that leads to an appropriate discharge location, such as the exterior of a building. It is not uncommon for these and other types of drain lines to occasionally become partially or completely clogged, resulting in a backup of condensate liquid in the drain line and the collection pan of the HVACR unit. In particular, the slow and continuous movement of condensate liquid through the drain line (i.e., by gravity transfer) encourages the growth and accumulation of algae, bacteria, dust, corrosive residue and other debris that builds up in the drain line and eventually causes a partial or complete blockage. The backup of condensate in the drain line and collection pan can result in an accidental overflow of condensate during the continuous operation of the HVACR equipment, possibly resulting in extensive and costly damage to the building structure and contents. This is a common problem that is well known in the industry.
In order to avoid clogs and accidental condensate overflows in HVACR condensate drain lines, it is recommended that the drain lines be cleaned (i.e., cleared of debris and residue) at least twice a year during normal maintenance procedures. Typically, cleaning of drain lines is achieved by introducing a pressurized flow of liquid or gas through one end of the drain line which serves to push debris, residue and blockages through the drain line and out through the opposite end. In most instances, when using a pressurized flow through the drain line for cleaning, it is desirous to gain access to the upper end of the condensate drain line near the air conditioner or refrigeration unit so that the pressure may be applied at the upper end, while pushing the clogging materials out through the opposite end, usually at an exterior of the building. Access to the upper end of the drain line requires detaching the drain line from the air conditioning or refrigeration unit and then replacing the drain line wherein the maintenance is completed. In many instances, access to the drain line can only be achieved by cutting the drain line near the HVACR unit to create an open end for injection of a pressurized gas or fluid. After cleaning, the cut drain line must then be repaired by inserting a connecting joint. This repair process compromises the water tight integrity of the drain line, and can often result in leaks at the repair joint.
In order to overcome the above-described problems associated with drain line clogs and maintenance for cleaning drain lines in HVACR systems, others have proposed for the installation of permanent inline assemblies that allow for access to the drain line to inject pressurized gas or liquid without the need of separating the drain line from the equipment or cutting the drain line. These various inline assemblies typically employ the use of a manually operated ball valve or gate valve that is closed during the clean out procedure so that the forced flow of gas or liquid is directed in one direction, usually away from the HVACR equipment. Use of a valve is advantageous in order to close off the drain line between the valve and a clog in the line. The pressurized flow of gas or liquid can then be introduced into the drain line between the closed valve and the clog, creating sufficient pressure to push the clog out through the line until the drain line is completely cleared of debris and clogging residue. However, after the cleanout procedure, the manually operated valve must be opened by the service person, otherwise the closed valve will act as a clog by preventing flow and draining of condensate liquid through the drain line to the desired discharge location.
The need to operate a manual shut-off valve in the various inline drain flushing systems of the related art presents several problems. In particular, the rotational force exerted on the manual valve control can cause bending or breaking of the drain line pipe and/or connecting joints, especially over time when the valve accumulates residue and tends to stick and resist movement. Eventually, the valve would need to be replaced which requires cutting the drain line at two locations. Another major concern with use of manually operated shut-off valves along an HVACR drain line is human error. If the service person forgets to re-open the valve after cleaning the drain line, the liquid condensate will not be permitted to drain out from the drain line and will, instead, back up into the HVACR unit drain pan, possibly resulting in an accidental overflow as the HVACR unit continues to operate.
Considering the foregoing problems and limitations associated with existing drain line clearance methods and devices, there exists a need for a drain line access device that is structured for inline installation to an existing drain line without obstructing the flow of drain line contents, and which permits convenient flushing of the drain line in both upstream and downstream directions. There is a further need for a drain line access device that includes an overflow safety switch within the housing of the device for disabling operation of an HVAC unit or other equipment connected to the drain line in the event of a clog/obstruction in the drain line that results in a back-up of liquid flow into the access device.